Minimum shaft positioning means



Sept. 22, 1959 w. J. ARMSTRONG ETAL 2,905,011

MINIMUM SHAFT POSITIONING MEANS Filed Jan. 22, 1957 6 0 26b 33b 2 a. 326

27a 52b 62a J/b A T'TORNE Y6 United States Patent 6) SHAFT Posmoun's'o 1Application January 22:, 1957, Serial No. 635,309

5 C a ms This invention relates generally to means for positioning apair of slideable members with a minimum. number of coupling devices.

Often, tunable plungers in an electronic waveguide must be separatelypositioned, and the positioning means must pass through electricalfields within portions of the waveguide. Patent application No. 579,639titled U.H.F. 1mpedance Matching Means of Edwin N; Phillips describessuch a waveguide device. It is, therefore, desirable to have a minimumnumber of positioning devices to minimize disturbances to the electricalfield. The plunger s are adjusted cooperatively to positions thatprovide a required impedance situation in the waveguide.

A conventional way of positioning such plungers is to connect one ormore shafts to each plunger, shafts connected to the first plungerslideably pass through openings in the second plunger. Thus, a ofoneshaft is. conventionally required per plunger, with two positioningshafts being required'fortwo piungers. The sheits ere generally ma i eedhe ih met i a ie 121eveht radiation ugh the openi n he eeeehd. plun er,but the conducting material eauses eleetrieai losses within thewaveguide. e

h invention pe mit red e eh b in -hal e minimum numberof shaftsnecessary to. obtain the abovementiened yp of p et en- Thu th n enti npe m ts a single shaft to independently position two plungers einvention u e a hr aded eheft w th e nsitudinal slot. The shaftthreadedly passes through one ad: iusieble member (w ic ma e a wa e ui ePlunger) and i rotetebly e ve but axial y h red. n a o he eeli s memberh the be; another a eguid plunger). Also, the shaft is threadedl yreoeived through a first driving means, which is rotatably held by aguide me t de b su p r s he st and. second ediusteble em see ed i ing mehe e se supported rotatably with respect to the guide; the shaftslideably passes throughit, except that the longitudinal slot in theshaft slideably engages .a key member fixed to the second drivingmeans.-

p e rotation of t e st nd seeeh dri ng means can independently p t n t eir and 2 14. ediheiehl members through the single shaft Further je e t ean advan a es of this. i venn l be pp e t a pe so hi ed in the a t nen fr r u y of e pe fiee ieh end sin e. fi u e. h eh is a partiallysectioned isometric view of a form of the invention.

NOW e e ng to t e aw n a u de .0. is ee p of an outer cylindrical member11 and an inner cylindrical member 12 concentrically supported by an endmember 13,. Guide may, for example, be a terminal part of a coaxial typeof waveguide used for the transmission of radio-frequency energy. Forelectrical reasons, a pair of plunger members 16 and 17 are requiredwhich must be separately positionable.

First plunger member 16 is a metallic disc having a central opening andis slideably received between the inner Pat n S p 22,, 9

n e t r e hdr e m mbe 2 en 11-. Se on p unger mpri e eh e metellie r ngn e er h telh n 21. and i mfn etr e meme: 23, Inner ring 21 is slideablyreceived about inner cylin drical niernber'lzj and outer ring 22 isslideably received against the inner surfaoe of outer cylindrical member11 A pair of shafts 26c; and 26b are provided to position plungers 16and 17. Here, the two, shafts obtain mechanb cal symmetry, due to the,central mechanical obstruction caused by inner conductor 12 However,only one of shafts 26a and 26b is required for the positioning functiontaught by this invention. For example, if inner cylindrical member 12were not there, a single shaft could be provided centrally with respectto the plunger members, which would have mechanical symmetry and couldpro vide the entire required positioning functions. Any number of shaftsmay be used to provide mechanical symmetry. However, must always berealized that only one of such shafts is necessary for the positioningfunctions obtained by this invention.

Accordifighl, each of the shafts 26g and 26b is formed in the samemanner; and the same reference numerais are used with respectfto eachshaft, except for a diiferent letter sufiix. Each shaft is threadedthroughout its length; except for its uppermost portion in the figure.Further, each shaft is forgrned with a longitudinal slot 271: or b whichextends through most of its length. In the figure, the uppernon-threaded portion of each shaft is rotatably' received by secondplunger member 17*. This portion is formed with a pair of grooves whichreceive retaining rings 25 that are positioned against opposite sides ofplunger 17 to bind them axially but topermit freerotation between them.The shafts 26a and 26b are also threadedly received through firstplunger 16. Thus, rotation of the shafts causes relative movementbetweenthem and first plunger 16.

First driving; members 2811 and 28b threadedly receive shafts 26a and26b and are supported axially by end member 13 through ball bearings 31,which are reoeived in races fixed with the respective members. Thus,first driving members 28a and 28b are fixed axially with re spect toguide 10- but can rotate relative to it.

A gear 32a or b is fa stened to the bottom end of each first driving,member 2801 and 2819; and a pair .offianges 33a and b and 34a and b arefixed on opposite sidesiof gears 32a and b. A ring gear 36 is formedwith inner and outerteeth, with its inner teeth engaging each of firstdriving members 32a and 32b. The flanges of the first driving memberprovide support for first ring gear 36. i

A first pinion 41 engages the outer teeth of first ring gear 36. Acontrol shaft 42 is fixed to pinion 41 and is rotatably and axiallysupported by a bearing 43 fixed with respect to guide 10. A firstcontrol knob 44 is fixed to the end of shaft 42. i

A pair of second driving members 51a and 51b is also received about therespective shafts 26a and b. Unlike first driving members 28a and 28b,each second driving member 51a and 51b does not threadedly engage itsshaft 26a or 26b. Rather, members 51a and 51b each have a key 52a or 52bfixed with it to slideably engage the longitudinal slot 27a or b formedinit-s shaft 26a or b. A gear 50a or b. bounded by a pair of flanges 53aor b and 54a 01' b is fastened to an end of each second driving member-5 1a or b. A second ring gear 56 has inner teeth which engage gears50aand 50b, I i

1 A e ie'p ien 57 engage h en r t e h et'sel eee ring gear 56 and has aflange 58 which provides support for second ring gear 56. A secondcontrol shaft 61 fixes a knob 62 to second pinion 57; and a bearing 63,fixed with respect to guide 10, rotatably supports: them.

The flange supports for the gears shown in the figure are merelyillustrative, and it will be obvious to a person in the art, after anunderstanding of the invention is obtained, how to provide supportingmeans for the various gears in a given situation.

. In operation, plunger members 16 and 17 can be independentlypositioned within guide by rotation of control knobs 44 and 62.Sufficient friction is assumed in the system so that either control knobcan be rotated without causing rotation of the other control knob. Ifsufficient friction is not inherent in the system, drag means (notshown) such as well-known types of worm-gears can be provided for gears41 and 57.

A positioning cycle is obtained by first positioning plunger member 16with first knob 44. (Although rotation ofknob 44 also moves secondplunger 17, its movement is unimportant at this time.) However, secondplunger member 17 is then singularly positioned by rotation of secondknob 62.

In more detail, when first knob 44 is rotated, second knob 62 isnon-rotative due to friction, and keys 52a and 52b are, therefore,non-rotative. Accordingly, threaded shafts 26a and 26b cannot rotaterelative to guide 10. Consequently, when first knob 44 is rotated underthese conditions, it causes rotation of first driving members 28a and28b through pinion 41, ring gear 36 and gears 32a and b. Since theshafts cannot rotate, the threaded actuation between each of them andtheir driving members 28a and 28b causes them to move longitudinallywithout rotation with respect to guide 10. Longitudinal movement Withoutrotation of shafts 26a and 26b obviously moves first and second plungermembers 16 and 17 together, maintaining a fixed spacing between theplungthreadedly receiving said shaft, a second driving member, saidshaft slideably received through said second driving member, a key fixedto said second driving member and slideably received in said shaft slot,first means for rotatably actuating said first driving member, andsecond means for rotatably actuating said second driving member.

2. Means for positioning a pair of plunger members slideably received ina guide, comprising a plurality of shafts, each threadedly engaging oneof said plunger members and rotatably engaging the other of said plungermembers, an axially-fixed connection being provided with said rotatableconnections between said shafts and said other plunger member, aplurality of first driving members, each rotatably supported but axiallyfixed to said guide, said shafts respectively and threadedly receivedthrough said first driving members, a first plurality of gears couplingsaid first driving members, a plurality of second driving members, eachslideably receiving a different one of said shafts, each of said shaftsformed with a longitudinal groove, a plurality of keys fixed to saidsecond driving members respectively and slideably engaging therespective slots of the received shafts, and a second 7 plurality ofgears coupling said second driving members.

ers. Thus, first plunger member 16 can be positioned where required byrotating first knob 44.

When second knob 62 is rotated and first knob 44 is non-rotative due tofriction, first driving members 28a and b are maintained non-rotative.Rotation of second knob 62, however, causes rotation of second drivingmembers 51a and 51b through gears 50a and b, 56 and 57; and,accordingly, shafts 26a and 26b are rotated because of their keyedconnection to second driving members 51a and 51b. Since first drivingmembers 28a and 28b are now non-rotative, the rotation of the shaftsthrough their threaded connections moves the shafts axially with respectto the guide 10. Accordingly, plunger member 17 moves with shafts 26aand 26b because they are axially connected. However, first plungermember 16 does not move with respect to guide 10, because each unit ofaxial movement of shafts 26a and 26b caused by their rotation in firstdriving members 28a and 28b causes them to move second plunger 16 backrelative to the shafts by an equal amount in the opposite direction,since the thread pitch is the same in each case. Accordingly, firstplunger 16 does not move relative to guide 10. Hence, only secondplunger member 17 is moved relative to guide 10 by the sole rotation ofsecond knob 62.

Although this invention has been dwcribed with respect to a particularembodiment thereof, it is not to be so limited as changes andmodifications may be made therein which are within the full intendedscope of the invention as defined by the appended claims.

We claim:

1. Means for positioning a pair of plunger members with respect to aguide member, comprising a shaft received through and threadedlyengaging one of said plunger members, said shaft rotatively received bythe other of said plunger members, means axially fastening said shaft tosaid other plunger member, said shaft being formed with a longitudinalslot, a first driving member rotatably supported by but axially fixed tosaid guide and 3. Shaft positioning means comprising a guide member,first and second plungers slideably received by said guide member toenable relative linear movement, a threaded shaft formed with alongitudinal slot, said shaft rotatably received by and axially fixed tosaid second plunger, and said shaft threadedly engaging said firstplunger, a first driving member rotatably received by and axially fixedto said guide member, said shaft being threadedly engaged by said firstdriving member, first means for selectably rotating said first drivingmember, a second driving member rotatably but axially fixed with respectto said guide member, said shaft passing through said second drivingmember, and a key locked with said second driving member and slideablyengaging the longitudinal slot in said shaft, and second actuating meansfor selectably rotating said second driving member. 4. A coaxialwave-guide having first and second plungers slideably received therein,a plurality of shafts, each shaft rotatably supported but axially fixedto said second plunger, each shaft threadedly engaging said firstplunger, and supporting means fastened to an end of said waveguide, aplurality of first driving members rotatably supported by but axiallyfixed to said supporting means, said first driving members threadedlyengaging said shafts respectively, a plurality of first gearsrespectively coupled to said first driving members, a first ring gearsimultaneously engaging said plurality of first gears, a plurality ofsecond driving members, each being axially fixed but rotatable withrespect to said wave-guide, said shafts respectively and slideablyreceived through said second driving members, said shafts respectivelyformed with longitudinal slots, a plurality of keys locked respectivelywith said second driving members and slideably engaging the respectiveslots of their received shafts, a plurality of second gears respectivelycoupled with said second driving members, and a second ring gearsimultaneously coupling said plurality of second gears.

5. Positioning means as defined in claim 4 having a first drive gearengaging said first ring gear, first knob means coupled to said firstdrive gear, a second drive gear engaging said second ring gear, andsecond knob means coupled to said second drive gear.

References Cited in the file of this patent UNITED STATES PATENTS2,796,587 Phillips June 18, 1957

